Reliability Analytics Corporation
Previous | Next      Search Home

First 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Last

First 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Last

Previous | Next      Search Home

2. INTRODUCTION 2.1 Motivation. This document was developed to address the appropriate mathematical and engineering practices during the materiel acquisition process for new military systems. Historically, these systems have required emergent technologies, and as such have presented a challenge in the upholding of system reliability standards. Thus, the guide aims to address the challenges presented through the application of techniques used to understand reliability concerns at the fundamental level, develop solutions to concerns as they arise, and validate the solutions as the design matures. The reliability concepts and methodologies presented within this guide have evolved from accepted commercial practice and actual application to Army, Marine, Navy and Air Force systems during their associated design and re-design lifecycles. 2.2 Scope. This guide is written as an overview for both the manager and the analyst. It extends coverage of the DFR process topics identified in GEIA-STD-0009 and expands upon the mathematical and engineering process steps required to ensure robust design. While this manual is intended to provide a general understanding of the concepts and principles required, and serve as an outline to robust design, it is not meant to be employed without project specific tailoring. When used in conjunction with project specifications, it should serve as a basis for identification and planning of the appropriate process steps that should be utilized during the design process thus improving the system reliability of fielded systems. 2.3 Organization. While the handbook has been organized by section title, it should be noted that many of the design practices covered are applicable at multiple stages of the design process. The six column matrix designed to relate the inputs and outputs of GEIA-STD-0009 is provided in Appendix A - SIX COLUMN MATRIX for review. A typical design lifecycle begins with definition of the initial requirements, the operational and environmental loads on the system, assemblies, subassemblies, and components. The initially proposed system design is laid out via block diagramming. This leads to system reliability model creation to investigate the interconnectivity of assemblies and components in turn allowing for the examination of cause and effect relationships inherent in complex multi-level systems. The utilization of block diagramming also helps in the determination of various failures points within the design. Examination of these failure points and relationships through top-down Fault Tree Analysis provides a system level view of potential loss of functionality. In addition, block diagramming facilitates component level failure mode analysis of system reliability using a Failure Mode and Effect Criticality Analysis (FMECA) or Failure Mode and Effect Analysis (FMEA) approach. Early in the design processes, Highly Accelerated Life Testing (HALT) is utilized to expose early prototypes and existing components to the full range of expected operating conditions, within a controlled environment. Any deficiencies identified during HALT testing are inspected using a Physics of Failure (PoF) approach or are addressed directly in the refinement of the conceptual design. At this phase, PoF Computer Aided Design (CAD) practices including dynamic modeling and simulation, finite element stress and heat transfer 2

Toolkit Home

Reliability Analytics Corporation
reliabilityanalytics.com